Components such as spring clips in engines can experience surface wear from contact with other components under operational vibrations and dynamic forces. Sensors have been designed to provide real-time monitoring of component wear during engine operation. Such monitoring improves safety and reduces operating and maintenance costs by indicating a maintenance requirement before it causes damage or unscheduled outages.
It is known to place multiple sensors at different depths in a coating on a component surface to sense a depth of wear in real time. However, multi-layer sensors require significant extra work and expense to embed because each layer must be laid down separately. Generally, N sensors require about N times more work to install than 1 sensor. Also, placing sensors at multiple depths at a single location is problematic because sensor material is not a good wear material, so these sensors can cause spalling and can reduce the life of the wear material.